I am doing a persuasive essay for English. I want a word that means "not located yet", as in if you know something exists, but have not yet found the boundaries where it exists. As in genetics, where you don't know the chromosome or area that a specific gene is found, therefore you cannot genetic-test for it.

The sentence is:

Instead of performing studies on many pairs of twins for the hope that one pair might have the [word I am looking for] gene, you could clone an individual already exhibiting the trait.

So the gene is not merely hypothetical — it actually exists but you just don’t know where it is?
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tchristDec 25 '13 at 23:40

1

The specific genes (multiple) do not have to be defective or anything, they should just be not well documented and detectable by a genetic test. Their location on the human genome is unknown, but they show evidence of existing. The traits that they give an increased chance of existing are important, so researchers want to know what environmental factors increase the chance of the gene expressing itself. But instead of experimenting on many pairs of twins for the hope that one of them might have the gene, researchers can clone an individual exhibiting said trait. Sorry for the scientific rant.
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FatimaDec 26 '13 at 17:13

not a rant at all, but a good clarification. In light of the above, I would vote against my own answer and call them the suspected or hypothetical genes, since they are not known to exist yet, therefore cannot be specified.
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medicaDec 28 '13 at 7:04

+1.Elusive is pretty much perfect. The alternatives are bland, inaccurate or both. Elusive will work nicely for persuasive writing and fits the required definition of something deduced or conjectured to exist while having yet to be definitively pinned down by hard evidence or rigorous experimentation.
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adamemdouglasDec 31 '13 at 1:08

Elusive also suggestions something that was difficult to find. Perhaps because it was hidden by other easier to find, but wrong, items. Perhaps because it was (eg an animal) actively moving to avoid detection.
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AdrianHHHDec 31 '13 at 14:15

In Caucasians, mutations in a gene called CARD15 make a person susceptible to Crohn's disease, but Japanese with Crohn's disease have none of these mutations. Presumably a different gene, yet to be found, contributes to Crohn's in Japanese.

unidentified, undiscovered, unnamed

...provided validation that the unnamed feeling was an Autonomous Sensory Meridian Response ...

Edited in light of new information ("as in if you know something exists, but have not yet found the boundaries where it exists...don't know the chromosome or area...)

desired

...restriction enzymes are used to cut the desired gene out of the DNA in which it is found.

The lower the number, the higher the chance that the desired gene will be expressed poorly.

...establish the function of the desired gene. ...the desired gene in a plastid... ...removed and replaced with the desired gene... ...enough offspring express the desired gene to make... ...the gene probe can only become attached to the desired gene.

It seems to me that the word specific fits perfectly there. The sentence you propose doesn't need to bring in the idea of unknown location at all. That could be left to other sentences that cover that topic to whatever degree you choose.